This invention relates to a vehicle suspension system that has a universal pivot with a transverse pivot axis between a hanger and a torque rod and a longitudinal pivot axis provided between the torque rod and an axle seat.
A suspension system having a universal pivot arrangement is known as shown in U.S. Pat. No. 4,541,653 issued to John E. Raidel. However, a suspension system of the kind shown in that patent provides a universal pivot by connecting a longitudinal bushing and a transverse bushing both to a hanger and mounting the forward end of a torque beam to one of the bushings. The torque beam is also connected directly to an axle and to an air spring or is essentially integral with an axle seat that is connected to the axle and the air spring.
In the several embodiments of the present invention, there is only one bushing supported on a transverse axis by a hanger, and a torque rod is journalled on the bushing to allow swinging movement of the torque rod in a generally vertical plane. There is an axle seat that is independent of the torque rod and that is connected to an axle and to an air spring. The air spring is thus mounted between the axle seat and the chassis of the vehicle.
A bushing assembly oriented on a longitudinal axis provides the connection between the torque rod and the axle seat. This longitudinal bushing allows relative rotation between the axle seat and the torque rod about a longitudinal axis because the longitudinal bushing constitutes the only connection between those components. Thus, a bushing assembly that provides the connection between the axle seat and the torque rod also completes the universal pivotal movement to accommodate various motions of the axle relative to the chassis. In all of the embodiments, the torque beam is easily removable with only a wrench. This permits ready access to other vehicle components as well as easy bushing replacement.
The first two embodiments described are for installation on a car van trailer where vertical space is limited. In both of these embodiments, the axle seat is underslung relative to the axle and is generally below the torque rod.
In the first of these embodiments, the connection between the axle seat and the torque rod includes an additional bushing having an axis transverse to the vehicle that gives additional strength to the connection between the axle seat and the torque rod. The second embodiment incorporates a larger and stronger longitudinal bushing and allows the extra transverse bushing to be eliminated.
The third and fourth embodiments described are similar to one another in that both incorporate essentially the identical suspension components, except for a special tower. The third embodiment provides a suspension system for installation with a tag axle. The fourth embodiment utilizes the same components to provide a suspension system for installation with a steer axle. The difference between the two is the provision of a tower for the steer axle suspension. The tower is installed on the axle seat and the air spring is connected to the tower rather than directly to the axle seat. In this manner, the tower provides additional spacing of the steer axle from the frame so that the wheel carried on the steer axle will clear the frame when it turns and the brake chamber will clear the air spring. These third and fourth embodiments are particularly suitable for installation on a military vehicle.
The fifth embodiment described is heavier duty than the third and fourth embodiments. In the fifth embodiment, the axle seat is overslung relative to the axle and is generally above the torque rod, with a step down section where the air spring is connected. Special braces are provided for the connection between the torque rod and the housing of the longitudinal bushing. The suspension system of the fifth embodiment, like those of the first and second embodiments, can be installed on a vehicle having very limited vertical space available.
In a sixth embodiment, the axle seat is overslung and has a step down section where the air spring is mounted. Rather than by welding, the axle seat is connected to the axle by U-bolts. In addition, the bushing is mounted on the torque beam, and the axle seat is journalled on the bushing .